Oil seed crops are a significant agricultural commodity. Plant seed oils are major sources of essential polyunsaturated fatty acids for human diets and renewable feedstocks for chemical industries. The enzymes of the fatty acid synthase complex in the plastids of developing seeds are responsible for the biosynthesis of fatty acids that are channeled into the cytosolic acyl CoA pool to sustain triacylglycerol accumulation. Triacylglycerol (TAG) biosynthesis is located in the endoplasmic reticulum with glycerol 3 phosphate and fatty acyl CoAs as the primary substrates. There are three acyltransferases involved in the plant storage lipid bioassembly, namely the glycerol 3 phosphate acyltransferase (GPAT, EC 2.3.1.15), the lyso phosphatidic acid acyltransferase (LPAT, EC 2.3.1.51) and the diacylglycerol acyltransferase (DGAT, EC 2.3.1.20). These three acyltransferases catalyze the stepwise acylation of the glycerol backbone with the final step being the acylation of sn-1,2-diacylglycerol (DAG) by DGAT into the formation of TAGs, a biochemical process generally known as the Kennedy pathway. DGAT-mediated acylation of the glycerol backbone to produce TAG has been suggested as the rate limiting step in plant lipids accumulation. Thus, DGAT is a target in the genetic modification of plant lipid biosynthesis.